batter's box
Noun
Meaning
an area on a baseball diamond (on either side of home plate) marked by lines within which the batter must stand when at bat
Source: WordNetHypernyms
Examples
The toughest thing in hitting shouldn't be deciding when to swing. It is, for me, deciding when not to swing. You should be swinging from the time you get into the batter's box until something says don't swing.